The present invention relates to a seat belt retractor to be installed in a vehicle.
Conventionally, a seat belt apparatus is known, which is structured to protect an occupant in a vehicle by a seat belt (or webbing) restraining the occupant. For example, Japanese PCT International Application Publication 2003-507252 (the '252 Publication) discloses a structure of a seat belt retractor of a seat belt apparatus in which a spool (or a winding shaft) can be rotated for the winding and unwinding of a seat belt by an electric motor.
The technology described in the '252 Publication proposes a possibility of using an electric motor to conduct the seat belt winding action of the spool in the structure of the seat belt retractor. When this structure is used for the control (or the seat belt storing control) of the winding up of a seat belt in order to prevent the seat belt from being kept in the unwound state, the control is required to prevent making the vehicle occupant uncomfortable as much as possible.
Specifically, if the seat belt storing control employs such a structure that the seat belt winding action is conducted on the condition that the wearing of the seat belt is cancelled by releasing a tongue from a seat belt buckle, the control may make the vehicle occupant uncomfortable when the vehicle occupant releases the tongue from the seat belt buckle to cancel the wearing of the seat belt but changes his or her mind and decides to wear the seat belt again. In this case, the vehicle occupant must withdraw the seat belt against the winding force of the seat belt winding action, thus causing discomfort.
Therefore, the present disclosure has been made in view of the above problem and it is an object of the present application to provide a technology which relates to a seat belt winding action using an electric motor for preventing the seat belt from being kept in the unwound state and which is effective for reducing the risk of making the vehicle occupant uncomfortable.
For achieving the object, the present application is made. The present disclosure can be typically adapted to a seat belt retractor to be installed in an automobile. In addition, the present disclosure can be adapted to a technology for developing a seat belt retractor to be installed in a vehicle other than the automobile, such as an aircraft, a boat, a train, or a bus.